Shared implementation of the codingest CLI.
codingest builds/checks a .kgl code graph from a checkout or one or more
git revisions. The CodeTreeCommand subcommands (Build / Status) are the
binary's top-level commands.
Pure-Rust over the sibling codingest builder + kglite::api::io (no
libpython link in the standalone binary). The pip install codingest wheel
links this same library through _run_cli, so command parsing and behavior
cannot drift between the cargo binary and the console script.